Pagyra-js

A TypeScript-based HTML to PDF converter library with comprehensive CSS 3 support and advanced layout capabilities.

Features

Core Capabilities

• HTML to PDF Conversion: Convert HTML content to PDF with precise layout control
• Comprehensive CSS Support: Full CSS parsing, inheritance, and layout support
• Advanced Text Handling: Complete text layout with overflow wrapping, justification, and text transformation
• Font Management: Built-in font support with custom font embedding via @font-face
• Cross-Platform: Works in both Node.js and browser environments

Recent Additions (from CHANGELOG)

• Overflow Wrapping: Full overflow-wrap / word-wrap parsing and layout support
• Relative Units: Support for em/rem units using inherited/root font sizes
• Text Transformation: text-transform parsing and rendering (uppercase/lowercase/capitalize)
• SVG Stroke Support: stroke-dasharray and stroke-dashoffset for dashed line rendering
• CSS Variables: Custom properties with inheritance and var() function resolution
• Justified Text: Consistent justified spacing across all inline fragments

Installation

npm install pagyra-js

Usage

Minimal Example (HTML only)

import { renderHtmlToPdf } from 'pagyra-js';

// Minimal usage - only HTML is required
// Other parameters will use sensible defaults (A4 size, standard margins)
const pdfBytes = await renderHtmlToPdf({
  html: '<h1>Hello World</h1><p>This is a PDF generated from HTML!</p>'
});

Basic Example with Full Control

import { renderHtmlToPdf } from 'pagyra-js';

const pdfBytes = await renderHtmlToPdf({
  html: '<h1>Hello World</h1><p>This is a PDF generated from HTML!</p>',
  css: 'body { font-family: Arial; } h1 { color: blue; }',
  viewportWidth: 800,
  viewportHeight: 600,
  pageWidth: 800,
  pageHeight: 1100,
  margins: { top: 20, right: 20, bottom: 20, left: 20 }
});

// Save or use the PDF bytes
fs.writeFileSync('output.pdf', Buffer.from(pdfBytes));

Advanced Example with Custom Fonts

import { renderHtmlToPdf } from 'pagyra-js';

const pdfBytes = await renderHtmlToPdf({
  html: `
    <div class="container">
      <h1>Advanced PDF Example</h1>
      <p class="justified">This text will be justified and use custom fonts.</p>
      <div class="box">Styled box with border-radius</div>
    </div>
  `,
  css: `
    @font-face {
      font-family: 'CustomFont';
      src: url('/path/to/font.woff2') format('woff2');
      font-weight: normal;
    }
    body {
      font-family: 'CustomFont', Arial;
      font-size: 14px;
    }
    .justified {
      text-align: justify;
      overflow-wrap: break-word;
    }
    .box {
      width: 200px;
      height: 100px;
      background-color: #f0f0f0;
      border-radius: 8px;
      border: 1px solid #ccc;
    }
  `,
  viewportWidth: 1000,
  viewportHeight: 800,
  pageWidth: 1000,
  pageHeight: 1400,
  margins: { top: 30, right: 30, bottom: 30, left: 30 },
  fontConfig: {
    fontFaceDefs: [
      {
        name: 'CustomFont',
        family: 'CustomFont',
        src: '/path/to/font.woff2',
        weight: 400,
        style: 'normal'
      }
    ]
  }
});

API Reference

Main Functions

renderHtmlToPdf(options: RenderHtmlOptions): Promise<Uint8Array>

Converts HTML to PDF and returns the PDF as a Uint8Array.

Parameters:

Mandatory Parameters:

• html: HTML content string (the only truly required parameter)

Optional Parameters (with sensible defaults available):

• css: CSS styles string (defaults to empty string)
• viewportWidth: Viewport width in pixels (can be calculated from page size)
• viewportHeight: Viewport height in pixels (can be calculated from page size)
• pageWidth: Page width in pixels (defaults to A4 width: ~595pt/8.27in)
• pageHeight: Page height in pixels (defaults to A4 height: ~841pt/11.69in)
• margins: Page margins in pixels (defaults to standard A4 margins: ~36pt/0.5in all sides)
• debug: Enable debug logging (optional, defaults to false)
• debugLevel: Debug log level (optional)
• debugCats: Debug categories (optional)
• fontConfig: Font configuration (optional, loads built-in fonts by default)
• resourceBaseDir: Base directory for resource resolution (optional)
• assetRootDir: Asset root directory (optional)
• headerFooter: Header/footer configuration (optional)
• environment: Environment abstraction (Node/browser, optional - defaults to Node environment)

Note: While the TypeScript interface requires all parameters, in practice only html is truly mandatory. The playground server demonstrates how to compute reasonable defaults for other parameters using helper functions like sanitizeDimension() and resolvePageMarginsPx().

prepareHtmlRender(options: RenderHtmlOptions): Promise<PreparedRender>

Prepares HTML for rendering without generating the final PDF. Useful for debugging layout.

Returns:

• layoutRoot: Root layout node
• renderTree: Render tree structure
• pageSize: Page dimensions in points
• margins: Applied margins

CSS Support

Pagyra-js supports a comprehensive set of CSS properties:

• Layout: display, position, float, clear, z-index
• Box Model: width, height, margin, padding, border, box-sizing
• Flexbox: flex-direction, flex-wrap, justify-content, align-items, etc.
• Grid: grid-template, grid-gap, grid-auto-flow
• Text: font-family, font-size, font-weight, line-height, text-align, text-transform, overflow-wrap
• Colors: color, background-color, opacity
• Spacing: gap, margin-block, margin-inline
• Units: px, em, rem, pt, mm, cm, in, %
• Custom Properties: CSS variables with var()

Font Configuration

interface FontConfig {
  fontFaceDefs: Array<{
    name: string;
    family: string;
    src: string;
    data?: ArrayBuffer; // Font data (required for browser environment)
    weight: number;
    style: 'normal' | 'italic';
  }>;
}

Development

Project Structure

src/
├── core.ts                  # Core exports and types
├── html-to-pdf.ts           # Main HTML to PDF conversion logic
├── index.ts                 # Main entry point
├── browser-entry.ts         # Browser-specific entry point
├── css/                     # CSS parsing and styling
├── dom/                     # DOM node handling
├── html/                    # HTML parsing and conversion
├── layout/                  # Layout calculation engine
├── pdf/                     # PDF generation and rendering
├── svg/                     # SVG support
├── units/                   # Unit conversion utilities
└── ... (other modules)

Build Process

# Install dependencies
npm install

# Build the project
npm run build

# Run tests
npm test

# Run linter
npm run lint

# Run playground (Node environment)
npm run playground

# Run browser playground
npm run playground:browser

Development Scripts

• npm run build: Compile TypeScript to JavaScript
• npm run clean: Remove build artifacts
• npm run test: Run test suite
• npm run lint: Run ESLint
• npm run playground: Interactive development environment
• npm run playground:browser: Browser-based playground
• npm run build:browser: Build browser bundle

Browser Support

Pagyra-js can run in browser environments with some configuration:

import { renderHtmlToPdfBrowser } from 'pagyra-js/browser-entry';

// Use the browser-specific entry point
const pdfBytes = await renderHtmlToPdfBrowser({
  html: '<p>Browser PDF generation</p>',
  css: 'body { font-family: Arial; }',
  // ... other options
  environment: new BrowserEnvironment() // Provide browser environment
});

Examples

Check the playground/public/examples/ directory for various usage examples:

• Basic HTML to PDF conversion
• CSS layout demonstrations
• SVG rendering examples
• Advanced text formatting
• Custom font usage

Contributing

Contributions are welcome! Please follow these guidelines:

1. Fork the repository
2. Create a feature branch
3. Implement your changes
4. Add tests for new functionality
5. Run npm run lint and npm test
6. Submit a pull request

License

MIT License